Space station modules may be attached to each other utilizing various means. In particular, the International Space Station (ISS) utilizes Common Berthing Mechanisms (CBMs) consisting of a male (Active Common Berthing Mechanism or ACBM) and a female (Passive Common Berthing Mechanism or PCBM) portion that connect modules together and permit transfer of resources, cargo and crew between each module.
Payloads exposed to outer space (i.e. vacuum) conditions may be attached to a space station by a variety of means. In particular, the International Space Station utilizes Flight Releasable Attachment Mechanisms (FRAMs) consisting of a male (Active Flight Releasable Attachment Mechanism or AFRAM) and a female (Passive Flight Releasable Attachment Mechanism or PFRAM) portion that connects vacuum exposed payloads to the International Space Station and provides power, data line connectivity, and physical attachment of the vacuum exposed payload with the International Space Station.
In the case of the International Space Station, the FRAM sites are located far from the pressurized modules and have limited resources such as power and data lines and generally no thermal management system (e.g. active cooling loops) that are enjoyed by the pressurized modules.